scholarly journals Development of Gold Nanoparticle Micropatterns for the Electrical Detection of Proteins

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 528
Author(s):  
Geonwoo Lim ◽  
Kibeom Kim ◽  
Yuri Park ◽  
Myoung-Hwan Park
Keyword(s):  
Electrostatic Interaction ◽  
Fluorescent Proteins ◽  
Selective Adsorption ◽  
Protein Detection ◽  
Portable Equipment ◽  
Simple Method ◽  
Widespread Application ◽  
Neutral Ligands ◽  
Precise Interpretation ◽  
Positively Charged

Protein analysis can be used to efficiently detect the early stages of various diseases. However, conventional protein detection platforms require expensive or complex equipment, which has been a major obstacle to their widespread application. In addition, uncertain signals from non-specific adhesion interfere with the precise interpretation of the results. To overcome these problems, the development of a technique that can detect the proteins in a simple method is needed. In this study, a platform composed of gold nanoparticles (GNPs) was fabricated through a simple imprinting method for protein detection. The corrugated surface naturally formed by the nanoparticle assemblies simultaneously increases the efficiency of adhesion and binding with analytes and reduces undesired interactions. After forming the GNP micropatterns, post-functionalization with both cationic and neutral ligands was performed on the surface to manipulate their electrostatic interaction with proteins. Upon protein binding, the change in the electrical values of the micropatterns was recorded by using a resistance meter. The resistance of the positively charged micropatterns was found to increase due to the electrostatic interaction with proteins, while no significant change in resistance was observed for the neutral micropatterns after immersion in a protein solution. Additionally, the selective adsorption of fluorescent proteins onto the micropatterns was captured using confocal microscopy. These simply imprinted GNP micropatterns are sensitive platforms that can detect various analytes by measuring the electrical resistance with portable equipment.

scholarly journals Anomalous Laterally Stressed Kinetically Trapped DNA Surface Conformations

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Valery V. Prokhorov ◽  
Nikolay A. Barinov ◽  
Kirill A. Prusakov ◽  
Evgeniy V. Dubrovin ◽  
Maxim D. Frank-Kamenetskii ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Mechanical Response ◽  
Persistence Length ◽  
Strong Impact ◽  
List Type ◽  
Surface Charges ◽  
Monomolecular Films ◽  
Chain Approximation ◽  
The Impact ◽  
Positively Charged

Highlights DNA kinking is inevitable for the highly anisotropic 1D–1D electrostatic interaction with the one-dimensionally periodically charged surface. The double helical structure of the DNA kinetically trapped on positively charged monomolecular films comprising the lamellar templates is strongly laterally stressed and extremely perturbed at the nanometer scale. The DNA kinetic trapping is not a smooth 3D—> 2D conformational flattening but is a complex nonlinear in-plane mechanical response (bending, tensile and unzipping) driven by the physics beyond the scope of the applicability of the linear worm-like chain approximation. Abstract Up to now, the DNA molecule adsorbed on a surface was believed to always preserve its native structure. This belief implies a negligible contribution of lateral surface forces during and after DNA adsorption although their impact has never been elucidated. High-resolution atomic force microscopy was used to observe that stiff DNA molecules kinetically trapped on monomolecular films comprising one-dimensional periodically charged lamellar templates as a single layer or as a sublayer are oversaturated by sharp discontinuous kinks and can also be locally melted and supercoiled. We argue that kink/anti-kink pairs are induced by an overcritical lateral bending stress (> 30 pNnm) inevitable for the highly anisotropic 1D-1D electrostatic interaction of DNA and underlying rows of positive surface charges. In addition, the unexpected kink-inducing mechanical instability in the shape of the template-directed DNA confined between the positively charged lamellar sides is observed indicating the strong impact of helicity. The previously reported anomalously low values of the persistence length of the surface-adsorbed DNA are explained by the impact of the surface-induced low-scale bending. The sites of the local melting and supercoiling are convincingly introduced as other lateral stress-induced structural DNA anomalies by establishing a link with DNA high-force mechanics. The results open up the study in the completely unexplored area of the principally anomalous kinetically trapped DNA surface conformations in which the DNA local mechanical response to the surface-induced spatially modulated lateral electrostatic stress is essentially nonlinear. The underlying rich and complex in-plane nonlinear physics acts at the nanoscale beyond the scope of applicability of the worm-like chain approximation.

Biological Multilayer Films Assembled by Redox Polymer and HRP on Screen-Printed Carbon Electrode

2012 ◽  
Vol 571 ◽  
pp. 56-59
Author(s):  
Yu Fang Sha ◽  
Mei Zhao ◽  
Ming Quan Yang ◽  
Hai Xin Bai ◽  
Man Zhao
Keyword(s):  
Horseradish Peroxidase ◽  
Electrostatic Interaction ◽  
Electrode Surface ◽  
Multilayer Films ◽  
Carbon Electrode ◽  
Layer By Layer ◽  
Redox Polymer ◽  
Screen Printed Carbon Electrode ◽  
Positively Charged ◽  
Screen Printed

Biological multilayer films of redox polymer and horseradish peroxidase (HRP) were successfully assembled on a screen-printed carbon electrode using layer-by-layer (LBL) assembled method based on the electrostatic interaction. The screen-printed carbon electrode surface was modified by the positively charged redox polymer, and the negatively charged HRP by LBL method.

scholarly journals Electrostatic Interaction Between NS1 and Negatively Charged Lipids Contributes to Flavivirus Replication Organelles Formation

2021 ◽  
Vol 12 ◽  
Author(s):  
Yali Ci ◽  
Yang Yang ◽  
Caimin Xu ◽  
Cheng-Feng Qin ◽  
Lei Shi
Keyword(s):  
Electrostatic Interaction ◽  
Membrane Binding ◽  
Essential Factor ◽  
Charged Residue ◽  
Charged Membrane ◽  
Phosphatidylinositol Phosphates ◽  
Positively Charged ◽  
Er Membrane

Flavivirus replication occurs in membranous replication compartments, also known as replication organelles (ROs) derived from the host ER membrane. Our previous study showed that the non-structural (NS) protein 1 (NS1) is the essential factor for RO creation by hydrophobic insertion into the ER membrane. Here, we found that the association of NS1 with the membrane can be facilitated by the electrostatic interaction between NS1 and negatively charged lipids. NS1 binds to a series of negatively charged lipids, including PI4P, and a positively charged residue, R31, located on the membrane-binding face of NS1, plays important roles in this interaction. The NS1 R31E mutation significantly impairs NS1 association with negatively charged membrane and its ER remodeling ability in the cells. To interfere with the electrostatic interaction between NS1 and negatively charged lipids, intracellular phosphatidylinositol phosphates (PIPs) level was downregulated by the overexpression of Sac1 or treatment with PI3K and PI4K inhibitors to attenuate flavivirus replication. Our findings emphasize the importance of electrostatic interaction between NS1 and negatively charged lipids in flavivirus RO formation.

A carbon-based nanocarrier for efficient gene delivery

2021 ◽  
Author(s):  
Tahereh Kashkoulinejad-Kouhi ◽  
Shadi Sawalha ◽  
Shahrokh Safarian ◽  
Blanca Arnaiz
Keyword(s):  
Hydrogen Peroxide ◽  
Gene Delivery ◽  
Water Solubility ◽  
Chemotherapy Resistance ◽  
A549 Cells ◽  
Carbon Nanodots ◽  
Simple Method ◽  
Efficient Gene ◽  
Low Toxicity ◽  
Positively Charged

Aim: Several types of nanocarriers, most of which show significant cytotoxicity, have been developed to overcome the problem of gene-delivery barriers. Biocompatibility, low toxicity and water solubility of carbon nanodots (CNDs) are major advantages that recommend them as delivery systems. Materials & methods: We present a simple method to produce positively charged CNDs. Ethanolamine, ethylenediamine and hydrogen peroxide were utilized to synthesize these CNDs. Results & conclusion: Our results indicated that delivery of the CND–siGFP complex led to significant switching-off of the fluorescence of the GFP-expressing A549 cell. Next, the A549 cells were transfected with siRNA against BiP, which is a pivotal protein in the chemotherapy resistance of cancer cells. The expression levels of BiP decreased remarkably.

scholarly journals A Critical Factor for Quantifying Proteins in Unmodified Gold Nanoparticles-Based Aptasensing: The Effect of pH

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 98
Author(s):  
Dai Lu ◽  
Dong Zhang ◽  
Qian Zhao ◽  
Xiangyang Lu ◽  
Xingbo Shi
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Protein Detection ◽  
Critical Factor ◽  
Cost Effective ◽  
Protein Corona ◽  
Target Protein ◽  
Universal Method ◽  
Salt Addition ◽  
Positively Charged

Unmodified gold nanoparticles (AuNPs)-based aptasensing (uGA) assay has been widely implemented in the determination of many different targets, but there are few reports on protein detection using uGA. Here, we designed a uGA assay for protein detection including the elimination of interfering proteins. Positively charged protein can be absorbed directly on the surface of AuNPs to form “protein corona”, which results in the aggregation of AuNPs even without salt addition, thereby preventing target protein detection. To overcome this problem, we systematically investigated the effect of modifying the pH of the solution during the uGA assay. A probe solution with a pH slightly higher than the isoelectric points (pI) of the target protein was optimal for protein detection in the uGA assay, allowing the aptamer to selectively detect the target protein. Three proteins (beta-lactoglobulin, lactoferrin, and lysozyme) with different pI were chosen as model proteins to validate our method. Positively charged interfering proteins (with pIs higher than the optimal pH) were removed by centrifugation of protein corona/AuNPs aggregates before the implementation of actual sample detection. Most importantly, the limit of detection (LOD) for all three model proteins was comparable to that of other methods, indicating the significance of modulating the pH. Moreover, choosing a suitable pH for a particular target protein was validated as a universal method, which is significant for developing a novel, simple, cost-effective uGA assay for protein detection.

Abstract B18: A simple method to prepare oligonucleotide-conjugated antibodies for multiplex protein detection

2016 ◽  
Author(s):  
Haibiao Gong ◽  
Ilona Holcomb ◽  
Aik Ooi ◽  
Xiaohui Wang ◽  
Daniel Majonis ◽  
...  
Keyword(s):  
Protein Detection ◽  
Simple Method

scholarly journals Optimization of SUAV’s propeller in a hover

2020 ◽  
Vol 313 ◽  
pp. 00045 ◽  
Author(s):  
Jakub Hnidka ◽  
Dalibor Rozehnal ◽  
Karel Maňas
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Propulsion System ◽  
Simple Method ◽  
Widespread Application ◽  
Method Of Calculation ◽  
Propeller Design ◽  
Aerial Vehicles ◽  
Simplified Method ◽  
System Components ◽  
Overall Efficiency

Small unmanned aerial vehicles (SUAVs) have found a widespread application in past decades. However, as the criticality of the missions for which they can be used increases, the demand for improvement of their efficiency increases as well. The paper focuses on a propeller driven SUAVs of a multirotor type, equipped with an electric motor, battery and propeller. The paper presents a simplified method of calculation of the SUAV maximal endurance, if the characteristics of all components of the propulsion system are known. To improve the overall efficiency of the propulsion system of an SUAV, the correct combination of all propulsion system components is critical. However, the largest impact on the maximal endurance is, arguably, caused by the propeller. The paper proposes a simple method of optimizing the propeller characteristics for hover and compares the proposed propeller design with conventional and commercially available propellers.

Excited States of Fluorescent Proteins, mKO and DsRed: Chromophore−Protein Electrostatic Interaction Behind the Color Variations

2010 ◽  
Vol 114 (8) ◽  
pp. 2971-2979 ◽  
Author(s):  
Jun-ya Hasegawa ◽  
Takehiko Ise ◽  
Kazuhiro J. Fujimoto ◽  
Akihiro Kikuchi ◽  
Eiko Fukumura ◽  
...  
Keyword(s):  
Excited States ◽  
Electrostatic Interaction ◽  
Fluorescent Proteins

High-Density and Highly Surface Selective Adsorption of Protein–Nanoparticle Complexes by Controlling Electrostatic Interaction

2006 ◽  
Vol 45 (5A) ◽  
pp. 4259-4264 ◽  
Author(s):  
Kiyohito Yamada ◽  
Shigeo Yoshii ◽  
Shinya Kumagai ◽  
Isamu Fujiwara ◽  
Kazuaki Nishio ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Selective Adsorption ◽  
High Density

Interaction of Chlorpromazine with Bile

1971 ◽  
Vol 17 (10) ◽  
pp. 998-1001 ◽  
Author(s):  
A E Clarke ◽  
M A Denborough
Keyword(s):  
Electrostatic Interaction ◽  
Cholestatic Jaundice ◽  
Carboxyl Groups ◽  
Optimum Conditions ◽  
Drug Molecules ◽  
Amine Groups ◽  
Protein Components ◽  
Positively Charged

Abstract Chlorpromazine causes precipitation both of the glycoprotein and protein components of bile in vitro. The reaction depends on an electrostatic interaction between the negatively charged carboxyl groups on the bile components and the positively charged amine groups on the drug molecules in solution. The optimum conditions for the interaction between chlorpromazine and bile components have been established, and the suggestion is made that this precipitation may be responsible in part, for cholestatic jaundice associated with the administration of chlorpromazine.

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